Measurement and temperature dependence of the water vapor self-continuum between 70 and 700 cm$^{-1}$

Abstract

We present new measurements and analysis of the water absorption spectra in the region of the rotational band, between 70 and 700 cm^-1. The higher pressures of the recordings (up to 16 mbar) as compared to our previous measurements allowed us to extend the retrieval of the water vapor self-continuum absorption from 500 to 700 cm^-1 and to test our earlier results up to 500 cm^-1. As a result, the continuum amplitude at high wavenumbers, determined with smaller uncertainty, shows an improved agreement with literature experimental data. The measurements were performed at two temperatures (296 and 326 K) using two radiation sources of significantly different power ranges: SOLEIL synchrotron and globar. The quadratic pressure dependence of the self-continuum absorption was verified leading to consistent values of cross-sections derived at various experimental conditions. In addition, we obtained the first data concerning the water vapor self-continuum temperature dependence in the 84-365 cm^-1 spectral range for which we present the preliminary analysis considering the available measurements and theoretical data.

Olivier Pirali

Director of Research

My research interests includes high resolution molecular spectroscopy, laboratory astrophysics, and THz generation.